Abstract

The untufted, or gracile, capuchin monkeys are currently classiﬁed in four species, Cebus albifrons, C.
capucinus, C. olivaceus, and C. kaapori, with all but C. kaaporihaving numerous described subspecies.
The taxonomy is controversial and their geographic distributions are poorly known. Cebus albifrons
is unusual in its disjunct distribution, with a western and central Amazonian range, a separate range
in the northern Andes in Colombia, and isolated populations in Trinidad and west of the Andes in
Ecuador and northern Peru. Here we examine previous morphological and molecular hypotheses of the
taxonomy and phylogeny ofCebus. We construct a time-calibrated phylogeny based upon mitochondrial
DNA sequences from 50 Cebus samples from across their range. Our data indicate that untufted
capuchins underwent a radiation at about 2 Ma, and quickly diversiﬁed in both the Andes and the
Amazon. We provide a provisional reassessment for the taxonomy of untufted capuchins in the Amazon,
the Llanos, the Andes, Trinidad, and Central America, splitting currently paraphyletic taxa into
several species, including: at least two Amazonian species (C. yuracus and C. unicolor); a species from
the Guiana Shield (most likely the same as Humboldt’s C. albifrons); two northern Andean species, C.
versicolor, C. cesarae; C. brunneus (with trinitatis a junior synonym) on the Venezuelan coast, and C.
adustus in the region of Lake Maracaibo; C. capucinus in northwestern Ecuador and Colombia, and
Panama; C. imitator in Central America; C. olivaceus and C. castaneus occupying a large part of the
Guiana Shield; and C. kaapori in the eastern Amazon, south of the Rio Amazonas. More intensive and
extensive geographic sampling is needed, including that for some subspecies not represented here.
Taxa from the southwestern Amazon (yuracus, cuscinus, and unicolor) and the phylogenetic position
of Humboldt’s Simia albifrons from the Orinoco remain particularly poorly deﬁned. Am. J. Primatol.